Project Summary/Abstract Evidence demonstrates that sleep deprivation causes impaired cognitive function and is associated with impaired health (e.g. altered immune and cardiovascular function). Yet these conclusions largely derive from correlational relationships or studies of acute sleep deprivation lasting only a few days in sleep labs. Further, research on sleep in disadvantaged populations and sleep disparities is limited, despite severe environmental challenges to sleep among the poor. Moreover, the potentially bi-directional relationship between poor sleep and poor decision-making, a possible mediator of the income-health gradient, remains largely unexplored. In short, while poor sleep could be an important contributor to health disparities and accelerated aging, we know relatively little about the causes and impacts of sleep deprivation in low SES populations and how to address these disparities, a gap that is especially acute in ?real-world? settings with extended time frames. This K01 application will provide key training for career advancement and begin to close this gap in knowledge. To accomplish this goal, a randomized field experiment with 400 participants, each enrolled for over one month, in Chennai, India, will (1) objectively measure sleep and key environmental factors to provide preliminary evidence on the role of environmental causes of sleep deprivation in an urban environment, (2) rigorously evaluate two simple scalable interventions to reduce sleep deprivation among low-income adults in their natural environments, (3) estimate the causal effect of improved sleep on cognitive function, decision- making, health outcomes and behaviors (e.g. blood pressure, alcohol consumption), and earnings, and (4) utilizing questions regarding sleep asked of both RCT participants and a 50,000 person nationally-representative sample, estimate the extent of sleep deprivation and its impacts more broadly in urban India. The training aims underpinning the research aims and the applicant's long-term research goals are to expand knowledge and skills in: (1) cognitive psychology and the measurement of cognitive function, (2) aging, and (3) machine learning and predictive modeling. This training, accomplished through multiple avenues including coursework, directed study, and mentorship, will directly facilitate the proposed research and extend the scope and impact of the applicant's long-term research career studying health disparities and interactions between health and decision-making which may impact both cognitive and physical health as individuals age. Notably, while this application focuses on the impacts of sleep deprivation, the potential for health to shape decision-making is much broader. Constant exposure to other aspects of poor health associated with poverty, such as pain, also have the potential to exert a mental tax, leading to impaired cognition and poor decisions. Such a negative feedback loop between these factors and decision-making has the potential to further exacerbate health disparities. The far-reaching applicability of this idea beyond the direct scope of this proposal opens the door to high public-health significance through a wide variety of channels.